String and glue applicator for veneer

ABSTRACT

Apparatus for joining veneer strips which have been crowded into edge-to-edge abutting relationship and which are being conveyed in a direction substantially normal to their abutting edges. The apparatus includes a shoe pressed against the surface of the veneer strips for guiding uncoated string into contact with the veneer strips with the string extending across their abutting edges. Glue under pressure may be applied to the veneer prior to and after guiding the string into contact with the veneer or glue may simply be applied on top of the string. After the glue has been applied to the string the shoe presses the string, glue and veneer together to produce a bond therebetween.

United States Patent Primary Examiner-Carl D. Quarforth Assistant ExaminerBrooks H. Hunt Attorney- Kolisch & Hartwell ABSTRACT: Apparatus for joining veneer strips which have been crowded into edge-to-edge abutting relationship and which are being conveyed in a direction substantially normal to their abutting edges. The apparatus includes a shoe pressed against the surface of the veneer strips for guiding uncoated string into contact with the veneer strips with the string extending across their abutting edges. Glue under pressure may be applied to the veneer prior to and after guiding the string into contact with the veneer or glue may simply be applied on top of the string. After the glue has been applied to the string the shoe presses the string, glue and veneer together to produce a bond therebetween.

54 2 d 55 i I 22k 68 I I STRKNG AND GLUE APFLIICATOR FOR VENEER This invention relates generally to the manufacture of veneer and particularly to the manufacture of a continuous sheet of veneer from a plurality of strips of veneer.

in the manufacture of plywood large quantities of veneer are employed. The availability of sound, continuous sheets of veneer produced from peeler logs is continually becoming scarcer and thus, such veneer is very expensive and in inadequate supply. This has made it necessary to use peeler logs of lower quality containing more defects, many of which must be eliminated to make sound plywood. In removing such defects large quantities of veneer are produced in relatively narrow strip form, rather than as continuous sheets. Relatively narrow strips of veneer are also produced when a peeler log is not round and the veneer peeled therefrom comes off in noncontinuous sheets. Furthermore, plywood manufacturing techniques have been developed whereby it is possible to use veneer containing defects, particularly for core stock, as long as the pieces can be readily handled.

In manufacturing finished plywood products, it is generally desirable to produce relatively large finished panels, usually 4 feet by 8 feet, with the exterior plies of each panel preferably being continuous sheets of veneer which have lengths and widths corresponding to the full size panel. Thus the veneer strips are not best suited for exterior plies. It has been appreciated, however, that the strips of veneer can be useful in producing core material. To handle the core veneer strips conveniently it is desirable that multiple strips be joined in edgeto-edge abutting contact in composite sheets which have either the general dimensions of the finished panel or are adapted to be trimmed to such size. To produce such composite sheets it is possible temporarily to fasten veneer strips into edge-abutting relationship with each other by means of string or tape which will hold them together until such time as the exterior plies of veneer are bonded thereto to result in a finished plywood panel.

A general object of this invention is to provide novel apparatus for joining veneer strips in edge-to-edge abutting contact which is simple and economically constructed.

More specifically, an object is to provide such novel veneer strip joining apparatus in which a shoe is adapted to guide uncoated string into contact with the surface of the veneer strips with the string extending across the abutting edges of the strips and glue or adhesive supply and control means cooperating to dispense glue onto the string and veneer to produce a composite sheet of veneer.

Another object is to provide novel veneer strip joining apparatus in which the control means dispenses a predetermined amount of glue onto the string and veneer to produce an even bead along the veneer strips.

Yet another object is to provide in such novel veneer strip joining apparatus heated glue supply means permitting the use of thermoplastic glue.

These and other objects and advantages are attained by the invention and the same is described hereinbelow in conjunction with the accompanying drawings, wherein:

FIG. 3 is a side elevation of apparatus constructed in accordance with an embodiment of the invention for joining strips of veneer which have been crowded into edge-to-edge abutting contact and are being conveyed through the system by a pair of conveyor chains;

FIG. 2 is a reduced and simplified top plan view taken along the line 2-2 in FIG. 1 of the veneer strips conveyed through the apparatus and indicating the positions of a pair of guide shoes resting on the veneer;

FIG. 3 is an enlarged side elevation of a guide shoe in the apparatus illustrated in FIG. l with the near half of a major portion of the shoe broken away;

FIG. 4 is a bottom view of the guide shoe taken generally along the line 4-4 in FIG. I; and

FIG. 5 is an end elevation of the guide shoe taken generally ulong the line S- in FIG. 1.

Referring now to the drawlngs, and first more specifically to FIG. l, at to are indicated multiple, relatively narrow veneer strips which have been crowded into edge-to-edge abutting contact and are being conveyed along a path to the right in the figure by a pair of suitably driven conveyor chains l2, 14. As is seen in FIG. 2, the veneer strips all have substantially the same length. In FIG. 2, the direction of travel of the veneer strips is toward the bottom of the figure.

Indicated generally at 18 in FIG. I is apparatus constructed in accordance with an embodiment of the invention which is operable to join the veneer strips in their edge-abutting relationship.

The apparatus includes an elongated shoe 22 having the configuration illustrated, which rests upon the upper surface of the veneer strips. The shoe is positioned parallel to the path of movement of the veneer strips with its upstream end 22a to the left in FIGS. 1 and 3 and its downstream end 22b to the right. The underside of the upstream end portion of the shoe is beveled upwardly on progressing in an upstream direction, providing an inclined surface under which the strips of veneer may move. This bevel is provided to accommodate vertical misalignment between adjacent veneer strips.

Referring now specifically to FIGS. 3, 4 and 5, it will be seen that the shoe has a slot, or guide, 26 extending longitudinally along its lower surface. Slot 26 has a substantially constant width throughout a majority of the length of the shoe as is best seen in FIG. 4, however, as is seen in FIG. 3, there is considerable variation in the depth of the slot at different regions along the shoe. Referring to FIG. 3, it will be seen that the slot is rather shallow in a region 26a intermediate the upstream and downstream ends of the shoe and in a region 26b at the downstream end of the shoe. Region 26c of the slot, intermediate regions 26a, 26b, is concave to provide a deeper slot at this region. On progressing upstream from region 260 of the slot it will be seen that this region, denoted as 26d, is convex, sloping upwardly on progressing in an upstream direction. As seen in FIG. 4, the sidewalls 26e, 26fof the slot diverge in a region adjacent the upstream end of the shoe to give the slot at substantially V-shaped configuration when the shoe is viewed from above or below.

A supply port or passage, 30 is defined in an upper portion of the shoe and opens through the upper surface of the shoe. An orifice or discharge aperture, 32 having a much smaller diameter than port 30 extends downwardly from the lower end of the supply port and opens at its lower end within slot 26 in region 260 of the slot. Another orifice or discharge aperture, 36 extends at an angle downwardly from the lower portion of port 30, as is seen in FIGS. 3, 4 and 5, and opens at its lower end through sidewall 26e, upstream from region 260 of the slot, and closely adjacent the lower surface of the shoe.

Shoe 22 is supported in the apparatus from a channel beam 40, shown in cross section in FIG. 1, which extends above and transversely across the path of the veneer sheets. Supporting the shoe from beam 40 are a pair of parallel arms 42, 44 which are journaled adjacent one set of their ends to a plate 45 projecting outwardly from the beam, and adjacent their other set of ends to the vertical leg of an L-shaped member 46. A pair of bolts 48 extend through the horizontal leg of member 46 and into the side of shoe 22 to secure the shoe to member 46. With the shoe being supported in this manner it rests by virtue of its weight and that of the associated mechanism on the top surfaces of the veneer strips and may be raised and lowered with the parallel arm structure maintaining the lower surface of the shoe substantially parallel to the path of the veneer strips.

With the shoe thus supported uncoated string, such as that indicated at 50, may be threaded through slot 26 and guided by the shoe into contact with the upper surfaces of the veneer strips with the string extending across the abutting edges of the strips. As is best seen in FIG. 3 the string contacts the veneer strips adjacent region 260 of the slot, and thus this general area is referred to herein as a contact station. In a preferred application of the invention the string used comprises loosely twisted strands, or fibers, which lend themselves more easily to being flattened between sheets of veneer than tightly twisted string. It will be noted at this point also that orifice 36 opens into slot 26 upstream from the contact station and oriftce 32 opens into the slot downstream from the contact station.

The apparatus further comprises glue or adhesive supply means indicated generally at 52. The supply means is shown in simplified form and it includes a glue reservoir, pumping means for producing an above-atmospheric pressure in the reservoir, and heating means for heating glue in the reservoir thereby accommodating the use of thermoplastic glue or adhesive.

At 54 is indicated glue metering means which, as is best seen in H65. 3 and 3, is secured to the supper surface of shoe 22 and has a glue exhaust port which is connected through coupling 55 with supply port 30 in the shoe. As is best seen in FIG. I, a glue supply conduit 56 and a glue return conduit 58 interconnect the metering means and the glue supply means for supplying glue to and returning glue from the metering means, respectively. The metering means is of conventional design and is adapted to dispense a regulated flow of glue through port 36 and orifices 32, 36, into slot 26. The internal mechanism of metering means 54 is so constructed that glue supplied to the metering means which is in excess of that dispensed through orifices 32, 36 is returned to the supply means 52 through return conduit 58. In this manner when thermoplastic glue is used it is being constantly recirculated through the heating means so that it is maintained in a flowing state. Metering means 3, port 30, and orifices 32, 36 are referred to collectively herein as control means and the region in which they are positioned is referred to as a dispensing statron.

In order to expedite hardening of thermoplastic glue there may be provided a blower unit 66 which is supported above the upper surfaces of the veneer strips in a region immediately downstream from shoe 22. Blower 66 supplies a flow of coolant fluid (such as air, or an air-liquid mixture) at lower than ambient temperature onto the string and glue as they progress downstream with the veneer strips.

There may also be provided a pair of opposed rollers 68, 70 if it is desired to cause additional flattening of the glued string to the veneer. The rollers are journaled on parallel shafts downstream from blower unit 66, with roller 68 above and roller 70 below the veneer strips. The rollers are positioned to rotate in the direction of movement of the veneer strips and to apply a compressive force to string 50 and the veneer strips as they are conveyed through the apparatus.

Describing now the operation of the apparatus, veneer strips which have been previously crowded into edge-abutting relationship are conveyed to the right in FIG. 1 by conveyor chains l2, l4. Uncoated string 50 is threaded into slot 26 of the shoe and is secured at at least one point to a veneer strip so that it will be moved in a downstream direction with the veneer strips. As the string is moved with the veneer in a downstream direction it is guided into contact with the veneer at the contact station adjacent region 26a of slot 26, with the string extending across abutting edges of adjacent veneer strips as seen in H0. 2.

Thermoplastic glue, heated to a flowing state at supply means 52 and maintained in this flowing state until it is dispensed, is supplied through conduit 56 to metering means 54 and is then exhausted under pressure into port 30 of the shoe. A portion of the glue is dispensed in a predetermined amount through orifice 36 onto the upper surfaces of the veneer strips in a bead upstream from the contact station. Another portion of the glue from port 30 is dispensed through orifice 32 into the cavity above string 50 defined by region 260 of the slot. A bend of glue is thus applied to the veneer against which the string is then guided and a covering bead of glue is applied which flows over the string and onto the veneer.

Region 26b of the slot, at the downstream end of the shoe, being shallow, acts as press means to press the glue, string and veneer together. Glue supplied to the metering means which is in excess of that dispensed through the orifices is recirculated back to the glue supply means through conduit S8.

Since the string has not been preheated prior to entering the slot in the shoe it is at a lower temperature than the glue with which it comes into contact and thus, produces a cooling effect to aid in setting the glue. As the glue, string and veneer are conveyed downstream from the shoe, a flow of coolant fluid from unit 66 may be blown over the glue and string to further set the glue. The string, glue and veneer may then also be passed between rollers 68, 70 which act somewhat to flatten the string and glue against the strips of veneer.

With the string thus extending across the abutting edges of the veneer strips and glued to the veneer strips a composite sheet of veneer strips is formed which may be handled conveniently in subsequent panel layup process. It is generally desirable to provide such a string connection adjacent opposite side margins of a series of abutting veneer strips as illus' trated in FIG. 2 and in some cases it will be found necessary to provide intermediate string connections, depending upon the width of the series of strips. In such instances a plurality of apparatuses as described above may be placed at intervals spaced laterally across the path of the veneer.

it has also been found that in some cases it is unnecessary to provide a bead of glue on the surface of the veneer strips prior to placing the string in contact with the veneer. in such cases the application of a head of glue over the string which flows down and around the edges of the string has been found to be sufficient. In the apparatus illustrated, such an operation could be set up easily by merely plugging orifice 36 and permitting orifice 32 to continue to dispense glue onto the string and veneer.

While an embodiment of the invention has been described, variations are possible without departing therefrom. it is desired to cover all such modifications and variations as would be apparent to one skilled in the art and that come within the scope of the appended claims.

It is claimed and desired to secure by Letters Patent:

1. Apparatus for joining veneer strips positioned in edge-toedge relationship comprising a conveyor for conveying such strips in a direction substantially normal to their edges along a path, and

shoe means disposed adjacent said path,

said shoe means including a string-guiding slot defined therein facing strips conveyed in said path and generally paralleling the direction of movement of said strips, said slot being adapted to press string guided therein against strips on said conveyor,

said shoe means further including means for feeding liquid glue into said slot including a discharge aperture which opens into said slot to expel glue onto said string as such is guided by said slot. Serial No. 762,590

2. The apparatus of claim 1, wherein said slot extends in a straight reach substantially paralleling the faces of said strips where a string is pressed against said strips, and said discharge aperture is between the ends of said reach.

3. The apparatus of claim 1, wherein the means for feeding glue comprises a passage extending into said shoe means, and said discharge aperture comprises a constricted orifice communicating with said passage.

4. The apparatus of claim 1, which further comprises glue supply means including a reservoir for holding a mass of glue, heater means for heating such glue, a pump having an exhaust and an intake connected to said reservoir, a feed conduit connecting said exhaust and said discharge aperture for feeding glue under pressure to the aperture, and a return conduit for returning glue in excess of that expelled by said aperture to said reservoir.

5. Apparatus for joining veneer strips positioned in edge-to edge relationship comprising a conveyor adapted to convey such strips along a path in a direction substantially normal to their abutting edges,

a shoe positioned adjacent said path and having upstream and downstream ends with respect to the direction of travel of the veneer strips, and

glue supply means for supplying glue under pressure to the shoe,

said shoe including a string-guiding slot defined therein facing strips in said path and generally paralleling the direction of movement of said strips, said slot, progressing at a contact station intermediate the upstream and downstream ends of the shoe, being adapted to press string guided therein against strips on said conveyor with the string extending across the abutting edges of the strips,

said shoe further including an orifice communicating with said glue supply means extending through the shoe and opening into said slot in a region downstream from said contact station, for dispensing a predetermined amount of glue onto the string and veneer, and another orifice connecting with said glue supply means extending through the shoe and opening to a region upstream from said contact station for dispensing glue onto the veneer prior to the string being guided thereagainst,

said shoe additionally including means in a region downstream from said first-mentioned orifice for pressing the string, glue and veneer together.

6. Apparatus for joining veneer strips positioned in edge-toedge relationship comprising a conveyor for conveying such strips along a path in a direction substantially normal to their edges,

shoe means disposed adjacent said path,

said shoe means including a string-guiding slot defined therein facing strips conveyed in said path and generally paralleling the direction of movement of said strips, said slot being adapted to press string guided therein against strips on said conveyor with the string extending across the abutting edges of the strips,

said shoe means further including means for dispensing a predetermined amount of glue onto the string in the form of a discharge aperture opening into said slot operable to dispense glue onto a string as such is guided by said slot and,

means for circulating glue joining with said discharge aperture including a reservoir, a supply conduit connecting the reservoir and the shoe means for feeding glue to said discharge aperture, and a return conduit connecting the reservoir and the shoe means for returning glue in excess of that dispensed through the discharge aperture to the reservoir. 

2. The apparatus of claim 1, wherein said slot extends in a straight reach substantially paralleling the faces of said strips where a string is pressed against said strips, and said discharge aperture is between the ends of said reach.
 3. The apparatus of claim 1, wherein the means for feeding glue comprises a passage extending into said shoe means, and said discharge aperture comprises a constricted orifice communicating with said passage.
 4. The apparatus of claim 1, which further comprises glue supply means including a reservoir for holding a mass of glue, heater means for heating such glue, a pump having an exhaust and an intake connected to said reservoir, a feed conduit connecting said exhaust and said discharge aperture for feeding glue under pressure to the aperture, and a return conduit for returning glue in excess of that expelled by said aperture to said reservoir.
 5. Apparatus for joining veneer strips positioned in edge-to-edge relationship comprising a conveyor adapted to convey such strips along a path in a direction substantially normal to their abutting edges, a shoe positioned adjacent said path and having upstream and downstream ends with respect to the direction of travel of the veneer strips, and glue supply means for supplying glue under pressure to the shoe, said shoe including a string-guiding slot defined therein facing strips in said path and generally paralleling the direction of movement of said strips, said slot, progressing at a contact station intermediate the upstream and downstream ends of the shoe, being adapted to press string guided therein against strips on said conveyor with the string extending across the abutting edges of the strips, said shoe further including an orifice communicating with said glue supply means extending through the shoe and opening into said slot in a region downstream from said contact station, for dispensing a predetermined amount of glue onto the string and veneer, and another orifice connecting with said glue supply means extending through the shoe and opening to a region upstream from said contact station for dispensing glue onto the veneer prior to the string being guided thereagainst, said shoe additionally including means in a region downstream from said first-mentioned orifice for pressing the string, glue and veneer together.
 6. Apparatus for joining veneer strips positioned in edge-to-edge relationship comprising a conveyor for conveying such strips along a path in a direction substantially normal to their edges, shoe means disposed adjacent said path, said shoe means including a string-guiding slot defined therein facing strips conveyed in said path and generally paralleling the direction of movement of said strips, said slot being adapted to press string guided therein against strips on said conveyor with the string extending across the abutting edges of the strips, said shoe means further including means for dispensing a predetermined amount of glue onto the string in the form of a discharge aperture opening into said slot operable to dispense glue ontO a string as such is guided by said slot and, means for circulating glue joining with said discharge aperture including a reservoir, a supply conduit connecting the reservoir and the shoe means for feeding glue to said discharge aperture, and a return conduit connecting the reservoir and the shoe means for returning glue in excess of that dispensed through the discharge aperture to the reservoir. 